Fetal intrahepatic Umbilical-Porto-Systemic venous shunts (IHUPSVS): In-utero anatomic classification

Highlights

• The fetal liver vascular network plays an important role in normal fetal growth and development.

• Deviation of blood from the liver by a shunt into the systemic circulation may alter this favorable function.

• Prenatal identification of these anomalies is mandatory for proper counseling and management of pregnancy.

• We present the first in-utero anatomic classification important for nomenclature standardization.

Abstract

Objective

Congenital intrahepatic shunts divert highly oxygen and nutrients rich placental blood flow from the liver into the systemic flow having a negative influence on normal fetal growth and postnatal development. The ability to recognize this anomaly helps assess the possible clinical impact, counseling, and management of pregnancy. The present study aimed to propose in utero classification for the Intrahepatic Umbilical-Porto-Systemic Venous Shunt (IHUPSVS) based on our experience.

Study Design

A prospective study. Grayscale ultrasound with two and three-dimensional high-definition Doppler modalities was used. IHUPSVS was defined as a diversion of blood from the liver tissue by abnormal communication between a branch of the intrahepatic Umbilical vein or the Portal veins with the systemic circulation (the Hepatic veins or the Sub-Diaphragmatic Vestibulum).

Results

Twenty-five fetuses were diagnosed with IHUPSVS. We identified three main anatomic types: I) Porto-hepatic shunt which was divided into Ia) regular single shunt (15/25, 60%) and Ib) regular multiple shunts, (6/25, 24%) II) Umbilical-Porto-Hepatic shunt divided into a) Umbilical or b) Umbilical combined with Portal hepatic shunt (2/25, 8%) and III) Cavernous- aneurysmatic shunt (2/25, 8%). All the shunts were verified by postnatal targeted sonography.

Conclusions

This study creates the anatomic basis for common nomenclature and future probable updating for this anomaly.

Introduction

Congenital Porto-systemic Venous Shunts are vascular malformations that diverge the intestinal blood flow into the systemic circulation bypassing the liver. This may lead to multi-systemic metabolic consequences with a variety of symptoms and long-term complications [1], [2], [3].

Traditionally, congenital Porto-systemic venous shunts are classified into extra and intrahepatic varieties. In the first, the communication appears outside the liver between the portal vein and the systemic venous circulation (Inferior Vena Cava, Renal, Iliac, etc.). In the intra-hepatic type, abnormal communication exists between any branch of the portal vein and a branch of the hepatic vein [4].

Our prior article [5] dealt with the general classification of all the Umbilical-Portal–Ductus Venosus systemic shunts with no specific reference to the various intra-hepatic anatomic variants on which this manuscript is focused.

The frequency of the intrahepatic Porto-systemic venous shunt in adults is estimated to be 1:4263 [6]. That of the extra-hepatic shunts is rarer and currently unclear.

A growing number of publications have appeared in recent years, showing an increasing interest in this anomaly [3], [7]. However, most of the literature is limited to children's and adults' clinical manifestations, methods of diagnosis, and treatment possibilities [8], [9], [10], [11].

With the development of high-definition prenatal ultrasound technologies and operator's skills, the prenatal diagnosis, and publications of these vascular abnormalities are reported more often [12], [13], [14], [15], [16]. A fundamental prerequisite for recognizing these shunts is acquiring the knowledge to examine the normal intrahepatic venous network [17], [18].

At present, the only intra-hepatic Umbilical-Portal-systemic venous shunt (IHUPSVS) anatomic classification was published thirty years ago by Park et al [19]. This classification was based on one case report and a retrospective review of other 13 patients between the ages of 50 and 75 years with chronic hepatic diseases which per definition are not congenital. As so, their application to in-utero life is questionable.

Therefore, there is a need 1) for an updated in-utero classification 2) to raise awareness of the various anatomic variants of this sub-group of congenital shunts, and 3) to establish a common nomenclature that will contribute to more accurate prenatal diagnosis, counseling, and management.